<?php
/**
 * Classes, which help reading streams of data from files.
 * Based on the classes from Danilo Segan <danilo@kvota.net>
 *
 * @version $Id: streams.php 718 2012-10-31 00:32:02Z nbachiyski $
 * @package pomo
 * @subpackage streams
 */

if (!class_exists('POMO_Reader')):
    class POMO_Reader
    {

        var $endian = 'little';
        var $_post = '';

        function POMO_Reader()
        {
            $this->is_overloaded = ((ini_get("mbstring.func_overload") & 2) != 0) && function_exists('mb_substr');
            $this->_pos = 0;
        }

        /**
         * Sets the endianness of the file.
         *
         * @param $endian string 'big' or 'little'
         */
        function setEndian($endian)
        {
            $this->endian = $endian;
        }

        /**
         * Reads a 32bit Integer from the Stream
         *
         * @return mixed The integer, corresponding to the next 32 bits from
         *    the stream of false if there are not enough bytes or on error
         */
        function readint32()
        {
            $bytes = $this->read(4);
            if (4 != $this->strlen($bytes))
                return false;
            $endian_letter = ('big' == $this->endian) ? 'N' : 'V';
            $int = unpack($endian_letter, $bytes);
            return array_shift($int);
        }

        /**
         * Reads an array of 32-bit Integers from the Stream
         *
         * @param integer count How many elements should be read
         * @return mixed Array of integers or false if there isn't
         *    enough data or on error
         */
        function readint32array($count)
        {
            $bytes = $this->read(4 * $count);
            if (4 * $count != $this->strlen($bytes))
                return false;
            $endian_letter = ('big' == $this->endian) ? 'N' : 'V';
            return unpack($endian_letter . $count, $bytes);
        }


        function substr($string, $start, $length)
        {
            if ($this->is_overloaded) {
                return mb_substr($string, $start, $length, 'ascii');
            } else {
                return substr($string, $start, $length);
            }
        }

        function strlen($string)
        {
            if ($this->is_overloaded) {
                return mb_strlen($string, 'ascii');
            } else {
                return strlen($string);
            }
        }

        function str_split($string, $chunk_size)
        {
            if (!function_exists('str_split')) {
                $length = $this->strlen($string);
                $out = array();
                for ($i = 0; $i < $length; $i += $chunk_size)
                    $out[] = $this->substr($string, $i, $chunk_size);
                return $out;
            } else {
                return str_split($string, $chunk_size);
            }
        }


        function pos()
        {
            return $this->_pos;
        }

        function is_resource()
        {
            return true;
        }

        function close()
        {
            return true;
        }
    }
endif;

if (!class_exists('POMO_FileReader')):
    class POMO_FileReader extends POMO_Reader
    {
        function POMO_FileReader($filename)
        {
            parent::POMO_Reader();
            $this->_f = fopen($filename, 'rb');
        }

        function read($bytes)
        {
            return fread($this->_f, $bytes);
        }

        function seekto($pos)
        {
            if (-1 == fseek($this->_f, $pos, SEEK_SET)) {
                return false;
            }
            $this->_pos = $pos;
            return true;
        }

        function is_resource()
        {
            return is_resource($this->_f);
        }

        function feof()
        {
            return feof($this->_f);
        }

        function close()
        {
            return fclose($this->_f);
        }

        function read_all()
        {
            $all = '';
            while (!$this->feof())
                $all .= $this->read(4096);
            return $all;
        }
    }
endif;

if (!class_exists('POMO_StringReader')):
    /**
     * Provides file-like methods for manipulating a string instead
     * of a physical file.
     */
    class POMO_StringReader extends POMO_Reader
    {

        var $_str = '';

        function POMO_StringReader($str = '')
        {
            parent::POMO_Reader();
            $this->_str = $str;
            $this->_pos = 0;
        }


        function read($bytes)
        {
            $data = $this->substr($this->_str, $this->_pos, $bytes);
            $this->_pos += $bytes;
            if ($this->strlen($this->_str) < $this->_pos) $this->_pos = $this->strlen($this->_str);
            return $data;
        }

        function seekto($pos)
        {
            $this->_pos = $pos;
            if ($this->strlen($this->_str) < $this->_pos) $this->_pos = $this->strlen($this->_str);
            return $this->_pos;
        }

        function length()
        {
            return $this->strlen($this->_str);
        }

        function read_all()
        {
            return $this->substr($this->_str, $this->_pos, $this->strlen($this->_str));
        }

    }
endif;

if (!class_exists('POMO_CachedFileReader')):
    /**
     * Reads the contents of the file in the beginning.
     */
    class POMO_CachedFileReader extends POMO_StringReader
    {
        function POMO_CachedFileReader($filename)
        {
            parent::POMO_StringReader();
            $this->_str = file_get_contents($filename);
            if (false === $this->_str)
                return false;
            $this->_pos = 0;
        }
    }
endif;

if (!class_exists('POMO_CachedIntFileReader')):
    /**
     * Reads the contents of the file in the beginning.
     */
    class POMO_CachedIntFileReader extends POMO_CachedFileReader
    {
        function POMO_CachedIntFileReader($filename)
        {
            parent::POMO_CachedFileReader($filename);
        }
    }
endif;